马尔尼菲青霉菌鉴定要点及该菌酵母相体外药敏分析

目的了解马尔尼菲青霉菌(PM)鉴定要点及该菌酵母相体外药敏结果,以指导临床合理用药。方法收集某院2009—2016年23例PM感染患者血或骨髓的分离株,观察其菌落形态,采用E-test法分析酵母相PM对伊曲康唑、伏立康唑、两性霉素B、氟康唑的药物敏感性。结果 PM形态:组织标本瑞氏染色直接镜检,可见典型卵圆形或圆形有明显横隔的孢子,常位于巨噬细胞内;血培养标本革兰染色镜检,可见菌体两端钝圆略弯曲呈腊肠样,偶有分枝状,可见有横隔。PM为双相型真菌,28°C为菌丝相,产生红色色素扩散入培养基中;35°C为酵母相,并有各自典型的菌落形态特征。伊曲康唑、伏立康唑、两性霉素B、氟康唑对酵母相(35°C)PM的最低抑菌浓度(MIC)范围分别为0.002~0.016、0.012~0.125、0.002~0.500、0.500~16.000μg/m L。结论 PM的特征性菌落形态,以及骨髓和外周血发现的真菌孢子对该菌有诊断价值。该菌对伊曲康唑敏感性最强,其次是伏立康唑、两性霉素B,而氟康唑敏感性相对较弱。

Identification and in vitro antifungal susceptibility of Penicillium marneffei in yeast phase

ObjectiveTo understand the identification and in vitro antifungal susceptibility of Penicillium marneffei(PM) in yeast phase, and guide clinic antifungal application.MethodsStrains isolated from blood and bone marrow of 23 patients infected with PM in a hospital between 2009 and 2016 were collected, colony morphology of PM in yeast phase was observed, susceptibility to itraconazole, voriconazole, amphotericin B, and fluconazole were detected with E test method.ResultsColony morphology of PM were as follows: direct microscopic examination of Wright’s staining of tissue specimens found visible oval or round spore with apparent septum, and mainly located in macrophage; Gram staining of blood culture specimens found that strains were with bulbous and slightly curved ends, occasionally branched and with septum. PM was dimorphic fungi, presented mycelium at 28°C, produced red pigment and diffused into medium; PM presented yeast form at 35°C, there were typical colony morphology. Minimum inhibitory concentrations (MICs) of itraconazole, voriconazole, amphotericin B, and fluconazole to PM in yeast phase were 0.002-0.016, 0.012-0.125, 0.002-0.500, and 0.500-16.000 μg/mL respectively.ConclusionTypical colony morphology and fungal spore of PM in bone marrow and peripheral blood are important features for identification. PM is most susceptible to itraconazole, followed by voriconazole and amphotericin B, while fluconazole is less susceptible.